Hugh smith Vertical plate bending machine

Customer: Ministry of Works, Customer order No. P.O. Box 120, Wellington North, New Zealand.

Vertical Plate Bender - Hugh Smith

Vertical Plate Bender capable of bending plates with yield strength up to a width to diameters down to an inner diameter of 10 mm on 1 mm contact centers. Also, plates with yield strengths of minimum diameter are set out in the table.

The machine is complete with a set of high-speed piping and electrical equipment suitable for a supply of V, 3-phase, 50 cycles. We also include the services of one of our erectors to supervise erection and tests.

Weight: Approximately tons. Forged steel nose bar for fitting to plate roller. We also facilitate flanging.

Cranes: Two 5-ton electric radius cranes, for use with cranes. One set of hydraulically flattened floor plates, to bend STEEL PLATES.

A manual on the selection and use of PREFACE:

This publication has been compiled as a manual on the vertical hydraulic plate bending machine, full data for machine selection, and providing a useful reference book after installation.

Vertical Plate Machine - Hugh Smith has specialized since 1875 in bending machines of all types, and we believe our record in this field, and especially in the vertical bending, is worth recording in some detail, as very little on plate bending practice to date. The hydraulic vertical bender, an original Hugh Smith invention of 1890, and until 1953, the machine was operated by water from an accumulator station. In 1953, we introduced the self-contained electro-hydraulic machine, which reduced the cost and increased the efficiency. Since it could now be used by companies that did not have a hydraulic station, the power and versatility of the press, hitherto confined largely to boiler making, became available for the full range of plate and section working required in welded steel fabrication.

We make no claim that this manual is complete, but we sincerely hope that it will be a useful guide to the successful bending of steel.

PREFACE TO SECOND EDITION:

This manual has been well received, not only by engineers on fabrication work but also by technical students. The inclusion of practical data on plate flanging, on short heavy bending, and on the new Hugh Smith in-process measurement system will give additional useful information in this second edition.

Compiled by Hugh Smith Glasgow Ltd. Illustration: The main frame of heavy welded steel. Main bending and feed roller. Adjustable valve to control max. bending effort. Control desk. Facing rollers holding plate against the main roller. Stroke adjustment handwheel to control diameter. Reciprocating beam with bolted-on bolsters. Geared motor for turning the roller.

Various features of the design are patented.

CHAPTER 1: Introduction to the Vertical Bending of Plates

Why is the vertical bending of steel plates better than the older horizontal method? There are several good reasons for this.

First, the weight of the plate has very little effect on the bending accuracy. In horizontal rolls, it is necessary to support the plate on both sides as bending proceeds, whereas in the vertical machine, this is not required, and templates can be more accurately applied. Furthermore, the constant crane attendance necessary for horizontal rolls is eliminated. When the plate is entered vertically into the machine between the main feed roller and the vicing rollers, it is positively held and automatically fed through without the help of cranes. The lower edge of the plate rests on roller skates that can travel over the floor surface around the machine, thus taking the weight of the plate and, at the same time, maintaining alignment. This advantage is of even greater importance when bending red-hot plates because the vertical working prevents plate deflection and the need for constant support of the weight of the plate.

Second, for a given plate bending capacity, the vertical machine offers more power at a lower capital cost. This is of particular value when effective edge setting must be carried out in thick plates. The effectiveness of pre-bending the edge depends almost entirely on having sufficient power, and in this respect, the hydraulic vertical machine has a much better capacity than horizontal rolls, which must depend on screw adjustment for plate edge setting.

Third, the vertical machine is truly universal in that it can bend, for example, curves more easily, and it can also straighten heavy plates more easily. It is also very suitable for bending tanks, which would be almost impossible in a horizontal set of the same height requirements hold good for each type, especially if large diameter rolls or at least inconvenient work is to be done, but in some cases, a 12 ft. or higher vertical machine might require additional headroom for removing the completed shell.

Fourth, in the vertical machine, the scale that breaks away from the plate adds no friction effect on the bearings of the machine, leaving sometimes less than half the power of the machine for actual bending. The greatest loading or tonnage requirement for bending complete circles is when pre-setting the extreme ends of the plate. Theoretically, it is impossible to bend right to the end as to do so would require power or tonnage, but in practice a very small end flat is left on the plate if adequate hydraulic power can be brought to the gear as close to the end of the plate as possible.

Plate it is not simultaneously being rolled and, therefore, a high driving power is not required. It is particularly a type of heavy plates where exceptionally high loading. Due to the use of acting hydraulic rams, the Hugh Smith vertical bending or bending effort is required to bend to small diameters in minimum time. It is a press has exceptional capacity and is in fact superior to pinch type rolls, which often have the characteristic feature of pyramid or pinch rolls that the operation is slowed down and fails to preset the maximum thickness plate specified unless of exceptionally heavy, considerably when plates near the maximum capacity are being rolled due to the high and costly construction.

All plates in this Turbine Casing were formed in a Vertical Bending Machine.

Page 4 Introduction to the vertical bending of plates Advantages of the Hugh Smith machine We can summarize the advantages of the vertical hydraulic plate bending machine as follows:

The machine has ample power to bend even the heaviest plates to all diameters and down to smaller diameters than is possible with horizontal rolls. It also has adequate power for edge setting the heaviest plate, in contrast to conventional or pinch type rolls which lack this facility.

Due to the high power, the machine can bend plates in one pass or two passes, thus greatly increasing the output. Many drums can be produced in floor to floor times of 15 to 20 minutes, including edge setting.

Due to the versatility of the machine, a much wider range of work can be done, such as flanging, plate straightening, and forming cones, in addition to cylinder forming. In many shops horizontal rolls are for part of the time as they can be used only for one job, cylinder bending.

Horizontal rolls demand a great deal of crane time to support the ends of long plates while rolling. They also take up a lot of valuable floor space. The vertical working of the Hugh Smith machine requires little crane attendance, and the machine occupies a minimum of shop floor area.

Horizontal rolls lack the facility of drum correction after welding, the advantage of efficient red-hot bending, and the use of 'in-process measurement to speed output. All these are available on the Hugh Smith machine.

Page 5 CHAPTER 11 PLATE BENDING CAPACITY OF THE RANGE OF MACHINES It is not practicable to give complete lists of plates which can be bent on the machines due to the many variable factors involved. Although we publish maximum plate capacities for minimum drum diameters, these capacities are affected by such considerations as the amount of end flat permissible and the yield point of the steel being bent. Full-width plates slightly thicker than those given in the tables can be bent to larger diameters. The machines are also capable of bending thicker plates of lower widths, and we give in the following tables thicknesses for 4 ft. wide plates beaten close to the middle of the machine. In selecting a machine, it will be appreciated that the minimum diameter is limited by the need for adequate strength or rigidity in the roller around which the plate is bent. This places a natural limit on the production of small diameter drums. In practice, smaller diameters can be produced in shorter machines due to the reduction in span of the roller. Thus, it is not always the wisest choice to have the maximum width capacity as the extra width going from say 10 - 0 to 12 - 0 can limit minimum diameters if the minimum should be specially required. The power specified for the machines is based on the fully plastic condition of mild steel in the cold state; although in practice, the plate bends before becoming fully plastic throughout its thickness. Thus, our machines are conservatively rated, and it is only when edge setting that the full power of the machine is normally required.

Bending short thick plates To increase the capacity of a machine by including the bending of short cylinders from extra heavy plate and to very small diameters, it is necessary to support the main roller with a portable support table as shown on Fig. 1. For extra short cylinders to be bent in very heavy steel requiring the full hydraulic effort of the machine, such as for gearwheel rims, an upper roller support table can also be fitted as shown, chain-dotted, in the same drawing. This facility considerably extends the machine capacity. In pyramid bending rolls, this cannot be accommodated due to the constant adjustment necessary for the top roller.

Flanging When flanging it should be noted that if the radius to thickness ratio is as low as the steel stretches 20 at the outside fiber, and, therefore, the highest elongation of the steel should be maintained. For an acute or small radius 90 flange, there is a possibility of cracking the plate unless adequate ductility of the plate is ensured. The bending centers and minimum radii specified against plate thickness on page 14 are recommended. Plate ductility When cold bending thick plates 2 and over, the internal radius to thickness ratio R/T should not be less than 5. Although this corresponds to an elongation of only 10 approximately, in practice, this elongation before fracture is not greatly exceeded in the thicker plates due to the lack of rolling down or forging effect on the billet at the steelworks. In thinner plates, progressively smaller R/T ratios can be safely used down to unity for 1/8 thick ductile plates or sheets.

PLATE BENDING CAPACITY OF THE RANGE OF MACHINES FROM 150 TONS TO 5000 TONS ALL SIZES IN INCHES AND MILLIMETERS 1 TON = 2240 LBS.

MACHINE POWER, MAXIMUM 150 TONS 300 TONS 500 TONS 800 TONS 1200 TONS 2000 TONS 3000 TONS 5600 TONS

MAXIMUM PLATE WIDTH 

STANDARD ROLLER DIAMETER 

CIRCLE MINIMUM INSIDE DIA. 

FULL WIDTH PLATE THICKNESS 

AT REDUCED POWER TONS 

 WIDE PLATE THICKNESS 

WITH SMALLER ROLLER DIA.

CIRCLE MINIMUM INSIDE DIA. 

FULL WIDTH PLATE THICKNESS 

HORIZONTAL DAYLIGHT, MAX. 

MAXIMUM BENDING CENTERS 

AVAILABLE ON MACHINE 

MAX. MODULUS Z Elastic 

Plate Bending Capacity of the Range of Machines Notes on the Capacity Table Bending mild steel to small diameters

The capacities are based on mild steel of 16 tons per 25 kg. per All machines have sufficient power to maximally yield a point equivalent to an ultimate tensile strength of 28-32 tons per bend the rated plate thicknesses to all diameters down to a minimum inside sq. in. 44J50 kg. per mm. diameter of x roller diameter.

The plate widths heights in machine are standard 120 and 144. Other widths However, when bending smaller meters, the load necessary rises as capacities are also available. Plate thicknesses given are for all diameters down shown on the graph below. The top to x roller diameter. curve shows the percentage increased load required on the machine to

The minimum full circle inside diameter of a rolled cylinder is normally produce does x roller diameter. x roller diameter for cold mild steel, but see graph on this page. under the bending conditions shown in the diagram at left. To produce

The standard small diameter interchangeable. toller is chosen to operate at one still smaller diameters, a bar tool can quarter of full load except for the smallest machine, which is one third load. Other be inserted between the roller face and diameters of rollers are also available to suit specific requirements. the plate at the center of the machine. This tool is called a smith-bar; it

The alternative width of 48" is given for illustration only. The full range of reduces the power necessary and thicknesses widths is given on the calculator shown below. BEND CENTERS allows diameters as small as 1.1 x CONTACT CENTERS roller diameter to be produced, as

The maximum width is given for bars and sections. Note the rotation of shown on the graph below. bar depth due to horizontal daylight in the machine: When using full tonnage on short plates, there may be a tendency to dent or damage M is used in above Formula instead of N. the bending bars, and protective plates may be necessary.

To obtain the best results from the machine, it is important that the plate should be horizontal because it is possible more easily to move the plate between the move freely over the floor area, and roller skates of the type shown are bending strokes into the correct alignment of the radial lines. Supplied with each machine. These skates are designed to a maximum weight of 5 tons each and have a standard height of 3 from floor level. The plate should be prepared by finish cutting the development of the cone. height capacity of the machine is greater than the plate width and with Radial lines from the external apex of the cone must then be drawn on the plate with a spacing at the bottom edge of representing the amount of feed. A plate bending the underside of the top housing of the machine. diagram should then be made as shown in This diagram gives the amount of We wish to emphasize the need for accurately leveled steel floor plates around taper necessary on the bolster packing pieces and by adjusting these to the top and the working area of the machine and surface-ground plates having a standard area of can be supplied to make up the area desired, depending on the maximum in diameter. These plates should be accurately leveled within straight edge. The roller skates are supplied with a plain top roller to the flat bottom edge of the plate, but special profiled-roller skates can be supplied to suit any welding profile required. machine height divided by cone height multiplied by packing difference. For example, if the cone is high with a required difference in packing of the difference for Having ascertained the difference in bolster packing required for the cone, the same as bend forming, the two edges are preset first to the template. There are, of course, two templates, one for the top and one for the bottom of the cone. However, the production of cones is slower than cylinder forming because it is necessary between each alternative method to the above procedure has been successfully used, as bend to re-align the plate along the radial line. In practice, this can best be done by on stands equidistant from the center of the machine and just clear of the main roller and beam. The developed curved edges being the plate by means of jib cranes and where a fair amount of cone work is to is not required and the bending bars plate is fed by an amount equal to give the bending variation. Chapter 4 Bending Techniques - Flanging The High Smith vertical plate bending machine is capable of a wide range of flanging work, and the general flanging capacity is given below. This capacity is based on normal air bending of 90 flanges. Recommended bending centers and minimum inside radius with load all sizes in inches and millimeters. 1 ton = 2240 lbs. Plate thickness T. Bending centers Min. Inside radius R. Radius Ratio 1 TON LOAD RANGE Above thicknesses are for mild steel of max. yield stress. Load required for other plate widths are pro rata to 10 fc values. Existing Technology - Paying The machine can be used almost exactly in the same way as a hydraulic press CHAPTER Y brake and compared to a press brake the Hugh Smith machine has the following advantages:- BENDING TECHNIQUES - BARS Since the plate can be flanged around the main roller it is possible to form re- AND SECTIONS relatively small boxes. This cannot be done in a normal press brake due to the Since the vertical plate bender is equipped with automatic feed, the machine is proximity of the beam and can only be done with a swinging arm type bender, superior in speed and ease of handling to a conventional horizontal reciprocating which is a single purpose machine and relatively expensive. press for bending round, square, and regular bars, tubes, and certain rolled sections Press brakes are often fitted with horn extensions for making complete boxes or such as tee bars. However, the relatively small daylight inherent in the design of the complete circles. The same work can be done on the vertical machine and machine precludes the bending of deep sections such as deep I beams. for a much greater length than is possible with a horn extension. Furthermore, the much greater power in the vertical machine enables better and heavier work to be done than is possible with a horn extension. The vertical machine can form large corner radii more easily, for example round the roller itself rather than the flanging tool. Forming a true large radius on a press brake requires marking off, handling skill, and is much slower in operation. Where long plates have to be flanged these can be more easily supported on the roller skates in the vertical machine than is possible by slings from a crane on a press brake. The danger of back bending the plate due to its weight when using a press brake is eliminated. Plates are automatically lined up to the bending line quickly, provided the bottom edge of the plate is accurately square with the bending line. This is much faster than having to line-up both ends of a scribed line for flanging in a press brake. SPECIAL SHORT BAR STEEL ROLLERS USED NOTE: WHERE THIS PICTURE HAVE The above very real advantages are not gained without disadvantages and SHOULD BE HORIZONTALLY these are as follows: PLATE SIMILAR TO FIG. x The vertical arrangement is not so suitable for arranging repetitive punching unless a special bolster is fitted in place of the main roller. If this is done there FLG. 1 will be no duty. Along 8at ńar orx edge The machine is not so suitable for producing sharp radii on close centers unless a narrow flanging is fitted where Ø plates have to be flanged. However, in practice the machine bends a very useful range of bars. For convenience in this flanging bolster fitted to the vertical machine when the plate vicing handling the bars it is preferable to fit the portable table on the machine as shown rollers are vv thd àw, ñ with the moving beam. in Fig. 1. This table is in two sections, and for bending bars, the higher table should Page 15 4 Bending Techniques Bars and Sections be used. The support rollers fitted to the table top allow most bars to be held for bending of thin rings is a regular operation, corrective rollers can be fitted, but for feeding through by the hydraulic vicing roller provided. This arrangement ensures one-off jobs hammering the rings flat between passes is sometimes necessary. that the bar to be bent is firmly held against the main feed roller. The edge bending method is shown in Fig. 1. The method of bending bars is similar to place bending, progressive bending Tubes and round bars and feeding, but some sections can call for special consideration, and the following data It is essential when bending tubes to have external formers to support the walls is given for guidance. as shown in Fig. 2. For large diameter tubes, the support rollers must be removed from the table so that the vicing roller contacts the pipe close to the center. Regular bars Bending relatively thin bars on edge such as for drum flanges can be done, but care must be taken to ensure that the bar remains flat while bending. Where the SPECIAL SPLIT FORMER BOLSTERS SLOTTED TO SUPPORT TUBE WALLS ARTICULATED FORMERS SPECIAL ROLLERS TO PRESS ON INSIDE OF FLANGE WITH NO HOTEDGE PRESSURE ON WEB EDGE SPECIAL FO FIRING TOOLS ARE QUOTED FOR AGAINST SPECIFIC REQUIREMENTS 

Method of bending tubes and round bars. Bending tees. A heavy narrow plate being bent. Bending Techniques Bars and Sections. The special outer swiveling dies shown are recommended for small radius work and with this, a ratio of mean radius to pipe dia. of 4 to 1 is possible without filling the pipe or heating it. For large radius bends, the outer swiveling dies may be dispensed with, especially for thick steel tubes. Although the split former is recommended for each pipe size in steps, in some intermediate sizes packing pieces may be used. Solid round bars can also be easily bent without surface marking using these formers. Tee Bars. Bending tee bars is fairly straightforward using the method shown on Fig. 3. It should be noted, however, that when bending with the flange outwards, the relatively thin web tends to buckle and this must be controlled. With care, a skilled operator can produce a radius to depth ratio as low as 6 to 1 web out and 10 to 1 flange out with average rolled tees, or tees cut from H beams. Difficult Sections. Non-symmetrical sections such as angles or channels are difficult to bend due to the strong twisting tendency which cannot be easily controlled. For bending angles and channels, separate curving rolls should be used, especially for small radius stacks. Large angles can be curved to large radii in the Hugh Smith machine by tack welding Fig. 4 two together, back to back, to give a symmetrical tee section. For bending channels in the high modulus plane, they should be tack welded back to back to form an H beam, and in this state, a radius to depth ratio of about 8 to 1 can be achieved. The latter is also possible in rolled steel H beams except where the web is very thin relative and this is shown in Fig. 4. It is only necessary to reverse the 3 point bending system to the flange. The limiting factor here is the buckling of the web due to the pressure by the use of bars as shown, and the local overbending is easily pressed out. When the cylinder has been welded at the seam, as shown, a higher power is required to load or by fitting blocks between the flanges before welding. H beams can readily be bent the low modulus way down to 6 to 1, but care must be taken to see that the edge of the flanges does not damage the roller or the bolsters. Chapter VI. Red Hot Plate Bending. The vertical bending press is suitable for bending plates in the red hot state provided this feature is included in the original specification of the machine at the time of ordering. The main difference in specification is the fitting of a special alloy steel main roller which has physical properties of a type to reduce the effects of thermal shock. The latter has been the cause of roller breakages in the past, but the improved alloy practically eliminates the danger, provided the correct preheating procedure is adopted. Normally, steel plates need not be bent hot, as the cold ductility of the steel and the machine bending power are adequate for bending drums down to the smallest diameters used for. However, for bending very thick plates down to very small diameters as are required for high-pressure boiler work, red hot bending ensures freedom from surface fractures even with difficult materials. See paragraph on page 7 regarding cold plate ductility. In general, red hot bending doubles the thickness capacity of a given machine because the effective yield point of mild steel drops from a maximum of 20 tons per square inch cold to 5 tons per square inch at 900°C, i.e. cherry red heat bending resistance varies as the square of the plate thickness. The vertical plate bender has the following advantages over horizontal rolls for red hot bending:

Templating accuracy is greater due to the elimination of weight deflection.

The considerable amount of scale formed on hot plates drops clear and is not rolled into the plate, as happens with horizontal rolls.

The finished drum can be lifted out of the machine without danger of distortion. Strike while the iron is hot is literally true in bending drums, and speed is vital. The plate is normally heated to 950°C, and there is a working range of only 150 down to 800°C with the steel at a low yield point. Normally, a plate retains its working heat for only half an hour, and it is usually necessary to preset the 2 plate edges in one heat and complete the drum on a second heat. Special requirements for hot bending. The successful bending of drums in the red hot state calls for careful preparation of the following equipment:

Lifting Gear: The use of patent clamps such as the 'Camlok' is recommended as these very securely grip the plate without the need for welding on lugs.

Portable Screens: These are necessary to protect the operators and to retain the heat in the plate. The machine should have adequate fixed screening, and the portable screens should be pre-arranged around the machine.

Roller Skates: Due to the greater thickness of the plate to be handled, it may be necessary to use heavier models than the standard 5-ton skates.

Adjustable Height Platform: It is important that the operator should be able to reach the top of the plate quickly and easily for attaching and detaching the lifting gear, also templating.

Protective Clothing: It is necessary to provide the operators applying the template and attaching the lifting gear with the following: heat-resistant aluminum asbestos cloth knee-length coat and leggings to cover the operator's boots. Heat-resisting aluminum asbestos cloth knee-length coat and leggings to cover the operator's boots.

Conclusion Heat-resisting same material, but special glass visor. To up, most plate bending work can be and should be done cold, but where circumstances demand red hot bending it can best be done on the vertical machine, and the extra equipment necessary is not unduly expensive. Lighting. The protective glass in the operator's visor restricts the passage of It will be appreciated that the Cementer described on page is of particular value in the accurate bending of red hot plates. Page BENDING SPHERICAL PLATES Steel fabricators have always been shy of using plates curved in two because of the difficulty of plate forming and the expense of plate forming which is known for a great number of years, were reluctant to call for in the absence of an easy method of plate forming. The products parallel-edged spherical plates on a production basis of 2 to 4 lineal feet per minute with automatic feed. The plates are more easily formed in the vertical plane and they are fully supported on edge keeping them truly square as they move through the machine for progressive bending and forming. The type of male and female dies used are shown in Fig. They can be easily adjusted for bending a range of spherical rad. Advantages of Spheres. Designers are aware that a spherical vessel is the lightest for a given volume and pressure and has the smallest surface area for its volume. These attributes take on a new meaning when spheres can now be produced with low man-hours. It has been demonstrated that virtually all vessels having volumes equivalent to 20 ft. diameter, whether pressurized or not, can be made at lower cost than cylindrical vessels with domed ends. As the volume to be considered goes higher than this the lower weight of the sphere makes the lower cost still more attractive. Following on this the lower weight of the spherical vessel needs less expensive and less costly supports so the advantages are accumulative: Of further interest to the designer is the fact that the process does not involve and, therefore, any material such as 22 ton yield steel, stainless FIG. Page Bend Sp, ter c on P1 Ice5 FIG. Sphere constructed on the parallel plate system. The Hugh vertical bender is ideal for producing spherical plates on a continuous basis, thus giving a much higher output than possible by the traditional pressing method using a down-stroking ram. The procedure is to use normal parallel-sided plates and machine-bend the plates to the correct spherical shape, producing enough of these to meet full requirements. These plates can then be cut to the required profile from templates. The usual system is to have a circular bottom plate and then add petals taking the sides up to mid-height. These petals can easily be cut from standard plates and also the top and bottom circles can be formed from parallel or clad materials, aluminum, etc. can be safely used without the danger of changing sided plates. the characteristics of the material due to heat. An alternative method is to use the system shown on where the majority Hemispheres can also be produced very easily. In diameters above about 9. of plates are left parallel sided. For example, the Equator is a complete circle and it can be cheaper to produce in your own works spherical ends for cylindrical vessels the North and South are almost semi-circles. This system is claimed to show a saving of 25 in welding and 16 in material compared to the 'petal method. However, this system has not yet been used full size and the 4 ft. diameter sphere For the storage of water the unsightly rectangular or cylindrical vessel, especially is the only one built to date. if mounted high, is not now acceptable and the trend in recent years, especially in the United States, is towards the elegant tulip shape as shown in Fig. The stalk can be either wet or dry and for the larger sizes at least the lower weight of the sphere and cone results in a saving in cost. Page The above is on the basis of craneage being immediately available also that efficient plate support skates are used. SPEED OF Going. I mean diameter cone 5 0 max. 3 0 min. dia. . The maximum AND min; 1 incl L i co ri is reduced in proportion to the angle of the cone, but assuming g generally the large plate sizes as above, the following performance will be attained: The Hugh vertical bending machine operates at a plate speed of approximately 2 0 Setting plate in machine 4 per minute, depending on the selection of the variable length of 1 ced per Oe 1. End curling first end 4 End curling second end 4 Forming shell first pass 4 average feed including realigning plate in one pass. In practice, however, the operator would bring the plate close to the died diameter on the first pass and a second pass made to finish to size. Average plates can be bent in the vertical machine at approximately the same speed as horizontal pinch rolls but where the modulus of the plate is 75 or more of the maximum capacity the hydraulic machine has a better output. 60. The above is for producing several cones of the same size; if one off add 25 to the above times

Immediately available for transferring the plate from the edge setting press to the rolls. Time taken to fit tapered bolsters not included in above approximately 20 minutes. Next, what bending load is automatically taken off the plate while realigning for Performance of the Hydraulic Plate Bender the end in the core, thus speeding up the operation compared to conventional Any plate of the full capacity of the machine, max. height plate width by pyramids or pinch type rolls. max. thickness to be formed to a complete circle of say 36 diameter ready for Vote. =1 the above performance figures can be attained by a skilled operator after welding along the seam in approximately 25 minutes, detailed as follows: say 6 months experience. At first trials, the operator may take twice as long, and this Length of stroke 1; Speed 6 strokes cycles per min.; Length of feed 4. factor should be taken into account in fixing times. Therefore plate speed is 6 x 4 = 24 per minute. Alternatively, if the operator never attains these times, there is probably a fault Cylinders in site facilities or in procedure or in time and motion study. Setting plate in machine with one end ready for end curving 3 mins. Practical results End curving the first end 3 mins. Several companies report that in practice floor-to-floor times of 15 minutes on End curving the second end 3 mins. drums of about 4 ft. diameter have been attained, including edge setting. It has Forming shell first pass in 2-0 per minute average speed, ap- been found that performance greatly depends on continuity of work. Where drums proximately 5 minutes say 6 mins. are being continuously produced, an extremely high rate of production is maintained, For sizing of shell in the second pass including templating and but in jobbing shops, such production is not usually a requirement, and accuracy adjusting 8 mins. is of more concern. Removing a completed cylinder from the machine 2 mins. Requirements for high production Total door to door time 25 mins. If good production times are not being obtained, the following points should Larger diameters of shell take longer; a 10 -0 diameter shell would take be checked: 35 mins, assuming the same length of feed per bend, although this could be lengthened 1. The floor around the machine must be true and accurate within plus or minus to 6 so reducing time. 1/64 or a 10 ft. straight edge. Page 22 .

Speed of operation in performance 2. The roller of the machine must be truly perpendicular to the floor within the same tolerance or better. Due allowance must be made for the barreling of the roller in checking this.

The correct roller skates should be used and disposed around the machine to support the plate adequately.

For cylinder bending flange, the lower edge of the plate should be true to the required cylinder axis and should preferably be planed or milled for easy running on the roller skates.

The reciprocating stroke of the press should not exceed 1 for machines of 800 tons and above. For machines in the range of 150 tons to 500 tons, the stroke should not exceed 1 . As bending progresses, the back reversal point should be brought up to keep the stroke as short as possible.

The length of feed of the plate per bending stroke should not be too small, and in general, the feed should be between 2 and 3 times the plate thickness. On very small diameters, however, the feed should be restricted to the plate thickness value. Where wide bending centers are being used, say over 12, the length of feed The Hugh South Motor Frame Bender should not exceed one-third of the bending centers. CHAPTER 19 ELECTRIC MOTOR FRAME BENDER The current trend in the manufacture of electric motor and generator frames is equipped with automatic feed and hydraulic vicing of the plate exactly as for the full away from cast iron and onto welded steel. There are several advantages in all-steel height machines. construction, including freedom from breakage danger, lower cost, and even slightly smaller size. The breakage of parts of a motor frame, for example one of the feet, For producing a range of diameters, three or four sizes of interchangeable roller can mean considerable delay and expense: All this is virtually eliminated with a can be supplied and to facilitate easy interchange, a built-in electric hoist is normally fabricated frame. mounted over the roller, as shown in Fig. 1. This machine is included in the present series because it basically has the same operating characteristics as the machines for full width plate. However, the moving beam is operated by means of a single direct move without the need for backing gear or linkage to ensure parallelism. The machine can be supplied in two sizes, namely 600 tons and 300 tons in plate width capacities up to 4 ft. Because of the short span of the roller, the diameters produced can be extremely small for relatively thick plates. The machine is Page 23

PLATE AND BAR BENDING CALCULATIONS For a rectangular plate WL = Y X SHAPE FACTORS S FOR VARIOUS SECTIONS FIG. 1 Bending Difficulty Easy High the bending capacity tables cover most For a material which shows a yield stress the simple way way requirements for estimating the sizes, thicknesses, yield stress distribution is as shown in Fig. 1. The circle diameter diameters and material tensile strengths of drums moment that this section can withstand = YZp where rectangle produced on the respective machines. These graphs Y = yield stress and Zp = plastic modulus. For a H Beam 4 the above stress diagram is M = couple x distance equal angle This gives the relationship between the yield between them unequal angle point of the material and the other factors. 2 2 4 channel For a rectangle Zp = b d2 bulb flat However, in our plate capacity table on Page 8 the elastic modulus Ye = b d2 is used because engineering 4 bulb angle 2 6 SHAPE FACTOR For rolled steel profiles the values are approximate pocketbook tables give this value thus saving factor S is defined as plastic modulus only. calculation. elastic modulus OTHER FACTORS PLASTIC BOG THEORY. bdt bdg It should be noted that the above calculations do not Bending has to take place over a certain length in = for a rectangle. take into account the effect of shear set or the movement 4 6 the center. This is the end flat is normally taken to be one- of the neutral axis towards the compression side of the third of the bending axes it is reasonable to take the The BM equation can therefore be written plate or section whilst bending. In practice, the effect bending as acting over the central third. The BM at XX M = YZp = YSZ Z = elastic modulus of these is such for normal cylinder bending but therefore, extra bending load W is required for small diameter 6' 6' thick cylinders page 9 and 8anging page 14. HUGH SMITH GLASGOW LTD. Hamilton Road, Glasgow, Telephone: POST1820114 Telegrams: POSTIL, GOW Te1ea: 77640 Designers & Makers of The EDGE ROLLING MACHINE - TRU-EDGE EDGELINE - PLATE BENDING ROLLS PLATE STRAIGHTENING - the HYDROLEVEL PLATE STRAIGHTENING ROLLS - PLANING PR0 - GAP PROP OF ALL TYPES - HORIZONTAL GENERAL PURPOSE BR0 - NOTCHING

Guillotine - 4-COLUMN PRESSES - SHIPYARD ROLL PRESSES SHIP FRAME BENDING MACHINERY - Etc. Page 24